Yes, as a matter of fact I have. My closest 2 friends started going out with guys at 14-15. I was someone shy and certainly not ready for dating. They found different boyfriends around 16 and those relationships lasted (for a while). By the time I was 17 I hadn't been kissed much less had a boyfriend. I was starting to get more attention from guys but I was still shy and certainly wouldn't have flirted with a crush or even a guy I found attractive. So one of my guy friends (who happened to be dating one of the above mentioned girls) told me he had a friend who wanted to date me. Um...okay. So I said yes. I wasn't particularly attracted to him at first but he was a nice guy - and I had never met him before so I'm wasn't even sure how he knew who I was - but I started dating him. Weirdly, we didn't go on a few dates to get to know each other we just started "dating". I did this because I thought it was 'time'. He was a nice guy actually and we dated for 2 years!! But, I only dated him because I felt my own pressure and because, frankly, I thought my girlfriend's were looking down on me and that they thought I must not be good enough to get a boyfriend.
In the long run I'm not sorry it happened. Like I said, he was a nice guy and treated me very well. He was kind, respectful, etc. He was a good 'learning' boyfriend. I know that sounds terrible but he was safe for me to learn about relationships with. We both went our separate ways when I entered uni. Certainly isn't the right advise for everyone but yes, I did feel pressured to enter into a relationship but not from the guy.
Now that I've been to uni I understand that A LOT of people don't enter into their first relationships until uni or even afterwards. There is no set time table and if you feel your friends are judging you they may not be that great of friends. There is no right time or age to enter into a relationship and I don't suggest getting into one 'just because' but that is what I did..... and it was actually okay.